Multiple plots not working on the simulink spring mass model

In this pdf, page number 39, exericse 2 i tried implementing the same code using the same method but my output graph is like this. I have attachted my simulink file.

%for plotting graph

plot(out.t,out.x)

hold on

B = 8;

sim('second')

plot(out.t,out.x)

B=12;

sim('second')

plot(out.t,out.x)

B = 25;

sim('second')

plot(out.t,out.x)

hold off

%parameters

M=2; %kg

K= 16; %N/m

B=4; % Ns/m

Answer 1

[Fangjun Jiang]

This one again?

https://www.mathworks.com/matlabcentral/answers/646918-my-simulink-model-seems-to-not-receiving-proper-variables-from-workspace-or-not-returning-proper-val

[R Abhinandan]

hey, i need to superimpose graphs for different values of B like this

[Fangjun Jiang]

That is my point. You changed the value of B but the output didn't seem to change.

Read this linked Q&A. Change your code sim('second') to dummy=sim('second') and try again.

[R Abhinandan]

a=sim('second')

plot(a.simout.t,a.simout.x)

hold on

B = 8;

a=sim('second')

plot(a.simout.t,a.simout.x)

B=12;

a=sim('second')

plot(a.simout.t,a.simout.x)

B = 25;

a=sim('second')

plot(a.simout.t,a.simout.x)

hold off

this is my code and i get "Dot indexing is not supported for variables of this type." i changed my type from arrays to structure with time

[Fangjun Jiang]

Figure out what variable is your saved output. It could depend on your configuration setting, signal logging or ToWorkspace block.